/*
 *   This file is part of fastboot 3DS
 *   Copyright (C) 2017 derrek, profi200
 *
 *   This program is free software: you can redistribute it and/or modify
 *   it under the terms of the GNU General Public License as published by
 *   the Free Software Foundation, either version 3 of the License, or
 *   (at your option) any later version.
 *
 *   This program is distributed in the hope that it will be useful,
 *   but WITHOUT ANY WARRANTY; without even the implied warranty of
 *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *   GNU General Public License for more details.
 *
 *   You should have received a copy of the GNU General Public License
 *   along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */

#include <stdbool.h>

#include <types.h>
#include "hw/i2c.h"


#define I2C1_REGS_BASE  (0x10161000)

#define I2C2_REGS_BASE  (0x10144000)

#define I2C3_REGS_BASE  (0x10148000)


typedef struct
{
	vu8  REG_I2C_DATA;
	vu8  REG_I2C_CNT;
	vu16 REG_I2C_CNTEX;
	vu16 REG_I2C_SCL;
} I2cRegs;

static const struct
{
	u8 busId;
	u8 devAddr;
} i2cDevTable[] =
{
	{0, 0x4A},
	{0, 0x7A},
	{0, 0x78},
	{1, 0x4A},
	{1, 0x78},
	{1, 0x2C},
	{1, 0x2E},
	{1, 0x40},
	{1, 0x44},
	{2, 0xD6},
	{2, 0xD0},
	{2, 0xD2},
	{2, 0xA4},
	{2, 0x9A},
	{2, 0xA0},
	{1, 0xEE},
	{0, 0x40},
	{2, 0x54}
};



static void i2cWaitBusy(I2cRegs *const regs)
{
	while(regs->REG_I2C_CNT & I2C_ENABLE);
}

static I2cRegs* i2cGetBusRegsBase(u8 busId)
{
	I2cRegs *base;
	switch(busId)
	{
		case 0:
			base = (I2cRegs*)I2C1_REGS_BASE;
			break;
		case 1:
			base = (I2cRegs*)I2C2_REGS_BASE;
			break;
		case 2:
			base = (I2cRegs*)I2C3_REGS_BASE;
			break;
		default:
			base = NULL;
	}

	return base;
}

void I2C_init(void)
{
	I2cRegs *regs = i2cGetBusRegsBase(0); // Bus 1
	i2cWaitBusy(regs);
	regs->REG_I2C_CNTEX = 2;  // ?
	regs->REG_I2C_SCL = 1280; // ?

	regs = i2cGetBusRegsBase(1); // Bus 2
	i2cWaitBusy(regs);
	regs->REG_I2C_CNTEX = 2;  // ?
	regs->REG_I2C_SCL = 1280; // ?

	regs = i2cGetBusRegsBase(2); // Bus 3
	i2cWaitBusy(regs);
	regs->REG_I2C_CNTEX = 2;  // ?
	regs->REG_I2C_SCL = 1280; // ?
}

static bool i2cStartTransfer(int devId, u8 regAddr, bool read, I2cRegs *const regs)
{
	const u8 devAddr = i2cDevTable[devId].devAddr;


	u32 i = 0;
	for(; i < 8; i++)
	{
		i2cWaitBusy(regs);

		// Select device and start.
		regs->REG_I2C_DATA = devAddr;
		regs->REG_I2C_CNT = I2C_ENABLE | I2C_IRQ_ENABLE | I2C_START;
		i2cWaitBusy(regs);
		if(!I2C_GET_ACK(regs->REG_I2C_CNT)) // If ack flag is 0 it failed.
		{
			regs->REG_I2C_CNT = I2C_ENABLE | I2C_IRQ_ENABLE | I2C_ERROR | I2C_STOP;
			continue;
		}

		// Select register and change direction to write.
		regs->REG_I2C_DATA = regAddr;
		regs->REG_I2C_CNT = I2C_ENABLE | I2C_IRQ_ENABLE | I2C_DIRE_WRITE;
		i2cWaitBusy(regs);
		if(!I2C_GET_ACK(regs->REG_I2C_CNT)) // If ack flag is 0 it failed.
		{
			regs->REG_I2C_CNT = I2C_ENABLE | I2C_IRQ_ENABLE | I2C_ERROR | I2C_STOP;
			continue;
		}

		// Select device in read mode for read transfer.
		if(read)
		{
			regs->REG_I2C_DATA = devAddr | 1u; // Set bit 0 for read.
			regs->REG_I2C_CNT = I2C_ENABLE | I2C_IRQ_ENABLE | I2C_START;
			i2cWaitBusy(regs);
			if(!I2C_GET_ACK(regs->REG_I2C_CNT)) // If ack flag is 0 it failed.
			{
				regs->REG_I2C_CNT = I2C_ENABLE | I2C_IRQ_ENABLE | I2C_ERROR | I2C_STOP;
				continue;
			}
		}

		break;
	}

	if(i < 8) return true;
	else return false;
}

bool I2C_readRegBuf(int devId, u8 regAddr, u8 *out, u32 size)
{
	const u8 busId = i2cDevTable[devId].busId;
	I2cRegs *const regs = i2cGetBusRegsBase(busId);


	if(!i2cStartTransfer(devId, regAddr, true, regs)) return false;

	while(--size)
	{
		regs->REG_I2C_CNT = I2C_ENABLE | I2C_IRQ_ENABLE | I2C_DIRE_READ | I2C_ACK;
		i2cWaitBusy(regs);
		*out++ = regs->REG_I2C_DATA;
	}

	regs->REG_I2C_CNT = I2C_ENABLE | I2C_IRQ_ENABLE | I2C_DIRE_READ | I2C_STOP;
	i2cWaitBusy(regs);
	*out = regs->REG_I2C_DATA; // Last byte

	return true;
}

bool I2C_writeRegBuf(int devId, u8 regAddr, const u8 *in, u32 size)
{
	const u8 busId = i2cDevTable[devId].busId;
	I2cRegs *const regs = i2cGetBusRegsBase(busId);


	if(!i2cStartTransfer(devId, regAddr, false, regs)) return false;

	while(--size)
	{
		regs->REG_I2C_DATA = *in++;
		regs->REG_I2C_CNT = I2C_ENABLE | I2C_IRQ_ENABLE | I2C_DIRE_WRITE;
		i2cWaitBusy(regs);
		if(!I2C_GET_ACK(regs->REG_I2C_CNT)) // If ack flag is 0 it failed.
		{
			regs->REG_I2C_CNT = I2C_ENABLE | I2C_IRQ_ENABLE | I2C_ERROR | I2C_STOP;
			return false;
		}
	}

	regs->REG_I2C_DATA = *in;
	regs->REG_I2C_CNT = I2C_ENABLE | I2C_IRQ_ENABLE | I2C_DIRE_WRITE | I2C_STOP;
	i2cWaitBusy(regs);
	if(!I2C_GET_ACK(regs->REG_I2C_CNT)) // If ack flag is 0 it failed.
	{
		regs->REG_I2C_CNT = I2C_ENABLE | I2C_IRQ_ENABLE | I2C_ERROR | I2C_STOP;
		return false;
	}

	return true;
}
